Wheel spacers 1 - 1.5" questions

[Rice Nuker]

I have scored a set of sweet cobra wheels with F1 tires but the rear will require 1 to 1.5" of wheel spacers (have not measured, just estimating based on numbers). I will be buying friggin 3" arp studs and some-body's wheel spacers.

Do I need hub centric wheel spacers? Can the wheels just be stud centric and be right? I am running cobra rims.I plan to stack two 3/4" wheel spacers if necessary. Is my rim going to fly off in a hard corner when I downshift to 2nd and get sideways? If I ever get sideways..

 

[Rice Nuker]

What I am trying to do is avoid those spacers that have the studs built in and just run studs with spacers.

 

[grassy]

I cnnot remember the source but was told that the "spacers that have the studs built in" was far safer than just studs with spacers..i think it has to do with amount of contact...

 

[player1up]

Even some big trucks run bolt on wheel spacers. I've run spacers for years with no problems.
I prefer the bolt on kind. The main issue with plate spacers is that they move the force of the wheel farther out on the stud. Bolt on spacers introduce another set of studs to fail, but don't move the force to the very end of the stud. I would not use 3/4 plate spacers even if you could find them. There's a reason they don't make them...Although I think the spacer failure stories we all hear are due to them being loose.

As for hub centric rings / spacers, I guess it's better to have them but as long as the spacers are built well, they'll center the wheel on the studs. Remember, lots of aftermarket wheels aren't hub centric.
I forget what the runout on the wheel was when I checked mine but it was negligible.
I checked the lug nuts on the spacers every 100-150 miles for the first few weeks. Now I check them every time I do an oil change just to make sure they're tight.


BTW I run 2" spacers on the rear with my 360 with WFO shifts at least half the time ;)

 

[67Dart273]

Not sure I agree with your theory on studs. If the spacers / wheels are properly tightened, the sheer force is the short area between the hub and the spacer, and the spacer and the wheel.

Seems like a good idea to have a centering pilot at least on the hub side. A little work with a lathe would take care of that.

Rice, scare up a friend with a lathe and some aluminum, and MAKE 'em

 

[Rice Nuker]

Well, the only person I know with a lathe is 90 years old and his lathe is also 90 years old and I don't know him that well. Dangit.

I gotta get to know more people.

Not sure I agree with your theory on studs. If the spacers / wheels are properly tightened, the sheer force is the short area between the hub and the spacer, and the spacer and the wheel.

Seems like a good idea to have a centering pilot at least on the hub side. A little work with a lathe would take care of that.

Rice, scare up a friend with a lathe and some aluminum, and MAKE 'em

 

[ntsqd]

I cnnot remember the source but was told that the "spacers that have the studs built in" was far safer than just studs with spacers..i think it has to do with amount of contact...

I disagree. Wheel "Adapters" i.e. those with their own studs offset between the axle's studs, have HUGE unavoidable stress-risers built into them. If they were made from steel it wouldn't be a big deal. Being made from aluminum, Fatigue Life becomes a very large and important consideration. All of the loads have to go thru the adapter in a cyclic bending type of loading.

Ask this question on pretty much any 4x4 forum if you want to start a fight. Those who had one fail aren't all that common, but to a person none that I've ever seen post about them would use them again. The nay-sayers all say "they're fine", but they haven't tried to live through one of them failing. Yet. Those that have had them fail have some pretty grim stories to tell.

A true spacer, i.e. something that slips over the axle's studs, doesn't have this problem. The spacer is just that, a spacer. If the wheel studs are seeing bending loads the nuts aren't tight enough. Just like a flywheel, it is not the strength of the bolts (studs) in shear that transmits the power. It is the friction between the wheel's mounting surface and the face on the end of the axle that transmits the power. A spacer doesn't alter that, it just adds another pair of friction faces to the system. the same nut torque will clamp both sets equally.

Either type will place a large tensile load on the studs if the center of the contact patch is moved very far form stock. If I were to do this I'd want nothing less than ARP's premium wheel studs. And they need to be long enough that there is at least one stud diameter sticking out past the open end of each lug nut.

I'm not normally a "Sky is falling" kind of guy, but these scare me. Used appropriately (i.e. making up the difference in wheel back-space so that the tire ends up in the stock location) they're probably not a problem. Used badly, as most of them that I've seen are, they're a very big accident looking for a place to happen.

 

[Map63Vette]

... Used appropriately (i.e. making up the difference in wheel back-space so that the tire ends up in the stock location) they're probably not a problem. Used badly, as most of them that I've seen are, they're a very big accident looking for a place to happen.

I think this hits the nail on the head for a lot of the arguments I've heard. I have something like 1.25" spacers on my front wheels to make up the offset difference in my wheels (needed big offset for B body axle but wheels didn't have shallower version for fronts), but I'm using the bolt on "adapter" style. The contact patch is just about as close to the stock location as I can get it, so there shouldn't be any more bending and wheel bearing load than normal. Using them to increase the track width of the car would not be the best idea. I made sure to torque them down good on first install and have checked them a few times and they're holding nice and tight.

I would agree that aluminum wouldn't necessarily be my first choice because of fatigue issues, but they could be made from a nice high strength alloy that might help to mitigate this. A nice 7000 series aluminum would be awesome (have seen 7075 used in some projects I was involved with and it's some dang tough stuff), but I think most stuff tends to be 6061 which people claim is strong, but I tend to think of as soft based on the other alloys out there.

 

[RustyRatRod]

The spacers with studs are the best kind. Once installed, they basically become part of the hub. Those would be the ones I would want.

 

[ntsqd]

Highly doubt that any or many are made form 7075, too expensive for most consumer purchased products, especially when your competitors are using a less expensive alloy. Most likely they're 6061 or 6063 (extrudable version of 6061).

The spacers with studs are the best kind. Once installed, they basically become part of the hub. Those would be the ones I would want.

IF and only IF they're made from steel. Otherwise they are the worst kind. Unless fatigue failing them and having a wheel come off the car is a design goal.

 

[RustyRatRod]

Highly doubt that any or many are made form 7075, too expensive for most consumer purchased products, especially when your competitors are using a less expensive alloy. Most likely they're 6061 or 6063 (extrudable version of 6061).


IF and only IF they're made from steel. Otherwise they are the worst kind. Unless fatigue failing them and having a wheel come off the car is a design goal.

If you say so I guess. I know people who race on dirt that use aluminum spacers like I describe. They have not removed the spacers in literally several seasons and had no issues.

 

[player1up]

Not sure I agree with your theory on studs. If the spacers / wheels are properly tightened, the sheer force is the short area between the hub and the spacer, and the spacer and the wheel.

Seems like a good idea to have a centering pilot at least on the hub side. A little work with a lathe would take care of that.

Rice, scare up a friend with a lathe and some aluminum, and MAKE 'em

Yep, I should have said theory. I didn't mean to make it sound like it's an accident waiting to happen, just that it's beyond my comfort level. I've heard the stories, seen the pics...heck I've seen pics of broken wheels at an autocross...AND for all of the stories about failures, you'll see as many people chiming in about how they've used them for years without issues.

I still run bolt on spacers and check them often for anything out of the ordinary. I'll 100% agree that properly tightened is the operative phrase.

 

[ntsqd]

If you say so I guess. I know people who race on dirt that use aluminum spacers like I describe. They have not removed the spacers in literally several seasons and had no issues.

Most or all of those are Wide-5 (5 x 10.5" AKA '37 Ford BC) I'd guess. Which even though it seems like it should be the same, it isn't. It isn't because of where the studs are located, the leverage on them isn't near like there is with a much smaller BC.